The research proposed in the current grant year involves the study of the mechanism of action of flavoprotein oxidases. To this end several aspects of the flavoprotein oxidase, putrescine oxidase, will be examined. Transient state kinetics experiments will be done to more fully describe the kinetic component of the mechanism; these experiments will utilize a newly developed rapid-scan monochrometer computer system. Particular emphasis will be placed on examining the anomolous behavior of the enzyme during reduction by substrate and during reoxidation of reduced enzyme. In addition, research will continue into the essential features of the active site of putrescine oxidase as elucidated by photooxidation experiments and inhibition of the enzyme by amino acid specific reagents. Further work will also be directed at broadening the utility and power of the several computer controlled on-line instrumentation in the laboratory; particular emphasis will be placed on making the systems simpler to operate so as to make them useful to more experimentalists. BIBLIOGRAPHIC REFERENCES: DeSa, R.J. The Reduction of FAD and Flavoenzymes by Mercaptons. Proc. Fifth Intem. Symposium on Flavins and Flavoproteins (Singe, T.P., ed). p. 720, 1976. Faini, G.J., DeSa, R.J., and Lee, J. Rapid-scanning Stopped-flow Study of the Oxidation of FMNH2 by O2 Catalyzed by Bacterial Luciferase, ibid, p. 82, 1976.